After descending a few more kilometers, Liu Zai estimated that he had penetrated deep into the bottom stratum of the mountain, where the temperature began to rise, and the two sides of the rift valley were no longer the ice that would not melt for thousands of years. And Liu Zai can already hear the sound of the underground water flowing under his feet, the majestic sound of rushing is so familiar, Liu Zai has crossed the Yellow River twice, and he is no stranger to it.

The underground water flow not far from his feet is not weaker than the rolling Yellow River.

Groundwater, many people don't know about it, and think that it is just a source of water buried underground. In fact, it is the largest freshwater system on the earth except for the polar ice sheet, and the spatial distribution is intricate, forming a variety of underground streams, underground rivers, underground waterfalls, underground lakes in unknown corners of the earth, and some of them are even comparable to the world-famous rivers such as the Yangtze River and the Congo River. These are all untouched territories of mankind, and like the Ice Rift, no systematic scientific expeditions have been done so far.

People often compare the great rivers to the veins of the earth, but in fact they are just the exposed skin and capillaries of the earth's vast water system, and the real backbone of human beings knows nothing.

Liu Zheng, who is well-read and has the "Mountains and Rivers Society Map", naturally understands what a magnificent and wonderful world the underground is than many people in modern times, and the rock layer, water layer, magma and fire layer, as well as various energy element flows are intersecting and transforming, jointly assisting the surface to form a diverse ecological circle, and ninety percent of the earth's qi veins represented by the dragon vein run through here, and the part of the mountain range that appears on the ground is also just the tip of the iceberg.

The earth is really small, the universe is just a finger to ashes, and the world is really big, and there are countless wonders waiting to be discovered.

Human beings, really small.

This is the feeling of Liu Zheng, an underground dark river that is not inferior to the Yellow River is flowing endlessly, I don't know tens of millions of years, how many times have changed, how many dynasties have changed, the country is ruined, it still exists, look up and see that there is only one line left in the sky, and the world and the underworld are really only separated by this line. In the face of such a majestic nature, anyone will inevitably have the eternal awe of man-made ants.

"The ancients worshiped the gods and spirits mostly from nature, but there were people like him in ancient times who explored the spiritual veins of heaven and earth, and walked through the underground dark river, so that there would be the legend of the Huangquan Difu. Liu Zai thought to himself.

Estimated that the height difference between himself and the dark river under his feet was still 100 meters, but the rock wall gradually tilted inward, Liu Zai simply let go and jumped down the dark river from the rock wall, if there is a master who does not understand this scene, he will think that Liu Zai is crazy, even if the water depth is enough, jumping down at a height of 100 meters and smashing into the water is almost no different from directly smashing to the concrete ground, even if it is a congenital master, it will definitely die.

But Liu Zheng just jumped, has strength, and is willful.

In fact, he can fly down, but since the breakthrough of the innate he has been deliberately suppressed, and he has never used the "Kunpeng Wings" once, because what he wants is to soar into the sky, not to climb over the mountains and mountains.

Liu Zai manipulated the airflow buffer twice in mid-air with Long Xiang style and Fengyun Sanshou, slowed down the falling speed, adjusted his posture and plunged into the rolling dark river, and changed his breath, he felt that his diving technique was not bad for the first time in his life, and he could probably refresh the diving height record or something when he went to the Olympics.

"The water is not cold, about 7 to 8 degrees Celsius. ”

The current was very fast, Liu Zai recalled the direction, and turned over and dived into the dark river and swam upstream.

Liu Zai had not received formal swimming training before, and his swimming posture was not very suitable for people, but his legs were together to move forward, and his hands were only slightly assisted, like a fish and a dragon, although he was going against the current, his speed was not inferior to that of a clipper that set sail with the wind and water. This swimming posture is not suitable for the structure of the human body, it is the mode of action of aquatic mammals such as cetaceans and dolphins, Liu Zai's series of actions combine the physical and true element effects, not only suitable for the diving environment but also have the effect of assisting cultivation, naturally with the dragon walking style and the dragon Xiang style of the same source, called "hidden dragon style". Liu Zheng is now a half-dragon innate body, not only will he not get tired, but the more he swims, the more energetic he is, and the more energetic he is.

After tracing the water for a few hundred meters, the light is almost nothing, but fortunately, Liu Zai's eyes are extraordinary, his night vision ability is extremely strong, and he can see through the unknowable things such as energy and luck, and the dark river containing the power of the dragon vein shines like a golden river in the dark. Cave tributaries began to appear all around, extending in all directions like a labyrinth, the underground is dark, the signal is not through, it is impossible to identify the direction at all, ordinary people come here can be said to be called the sky should not be called the earth, and the explorers who are determined to go crazy after a long time.

Liu Zai is not afraid, he has an abnormal talent, the heart of the Tao is firm, there is no heaven and earth here, but the magnetic field is much clearer than the outside, and the golden dragon pupil follows the guidance of the dragon vein and water flow It is even more impossible to go the wrong way, plus the "Mountains and Rivers Society Map" in his mind, with this triple guarantee, it is difficult for Liu Zai to get lost, and he is secretly happy in his heart, the road of the heart to take the underground waterway is really the right one, if he is still outside the world, God knows where to catch the dragon vein.

In terms of material supply, he is not short of supplies, the food in the Xiao Sumeru ring is enough for him to spend several months, drinking water is everywhere, how long does it take for groundwater to be washed and filtered by rock formations, it is natural mineral water, ordinary people can drink it, and Liu Zai is of course no problem.

Moreover, this underground dark river is not without any creatures, after swimming for a long time, Liu Zai found a lot of burrowing fish without eyes and scales, and even formed a school of fish, the fat is nearly a meter long, I really don't know how this underground ecosystem supports these creatures.

Liu Zai suddenly thought that since these big fish need to form groups to protect themselves, it means that they are not at the top of the food chain, and there are bigger and more ferocious carnivores here.

Not panicked at all, Liu Zai hissed a little hideously, and a desire to hunt in his heart was about to move, he remembered the unlucky "Kunlun Bear King" on the snowy mountain.

Even if you really run into the overlord salamander here, it is not certain who will eat whom.

After swimming for a few more kilometers, the passage gradually narrowed, and the flowing water flooded the entire passage, and there was no room for further ventilation, and the speed of the water became more and more turbulent. Liu Zai had to dive completely into the water, relying on the pores of the whole body to absorb oxygen from the water, the biggest change of the congenital strong is the congenital fetal breath, no longer confined to mouth and nose breathing, so the survivability in the water has been greatly improved, history has not heard of a congenital strong person who drowned. This is an ability that all innate powerhouses have, not exclusively owned by Liu Zai.

However, this can only be urgent, after all, the innate strong are not aquatic animals, and once there is a vigorous exercise such as fighting, oxygen will not be enough.

The passage is getting narrower and narrower, and the speed of the water is getting faster and faster, and it is difficult to resist the strength of the water with the hidden dragon style alone, so Liu Zai has to grab the rock formation and lie under the water to advance. The turbulent undercurrent slapped on Liu Zao's body endlessly, like a peerless master with endless skills and another powerful palm technique, trying to push Liu Zao away.

Ten fingers deeply inserted into the rock formation under the body, against the momentum slowly forward dozens of meters, the water flow momentum reached the peak, Liu Zai estimated that the speed of the water flow has exceeded two hundred meters per second, equivalent to a thousand zhang high waterfall hit Liu Zai, the surrounding stone walls have been washed by the water flow over the years as smooth as a mirror, ordinary innate masters will also die early, Liu Zai has already used his whole body to resist, fortunately, this dark river contains a lot of dragon vein energy can be absorbed and replenished by the heaven and earth dantian, do not have to worry about the problem of exhaustion.

In such a dangerous situation, the concept of time and space began to blur, Liu Zai had to estimate the time through a balanced heartbeat, and after nearly two hours, he finally felt that the speed of the water began to slow down, and the cave gradually became wider. Moving on, swimming for a while, and finally being able to take a breath, Liu Zai stretched his head out of the water and inhaled fiercely, sure enough, breathing through the mouth and nose is the most comfortable, after all, I have been used to breathing for so many years.

In front of you is the ultimate darkness, there is really no light, this is an underground cave at least a few hundred meters underground, if there is light, you will see a ghost.

But Liu Zai's eyes were not dark, the pure dragon vein energy flow, the various elemental flows hidden in the underground, and the faint biological light emitted by various underground creatures all embellished this seemingly dead underground world with gorgeous colors.

"It turns out that there is no absolute darkness in the world, but the limitations of mortal beings cannot be discovered. Liu Zai said in his heart.

PS: The third watch is over, if you like it, please don't be stingy with the recommended monthly pass.